All of this said, healing agro is often way over stated on these forums. Pretty much the only place where it will ever really matter is titan, and even then only in early phases with groups that must endure a large number of rock slide -> stomps combos while building limit break. Once past this phase aoe healing tapers off. (Final phase, though more intense, the stomps are a minute apart, so the actual amount of healing done is lower).

Other than from a perspective of MP management, overhealing/not overhealling will have little-no effect on your play "quality." Really, if you are overly concenerend with overhealing, you will likely just risk letting the group fall behind on health and be more vunlerable. That said, this is why whm's tend to have much more hate than scholars.

If you are in any other situation (ie: not pre first jump on titan) and you are pulling threat as a healer, it is your tank's fault. Full stop. No "but in this sisutaion when the winds are blowing ot the west and its astral weather and teh opo-opo king is in moons" situations exist. There simply isn't a reason a healer should be pulling threat because healing has a low modifier relative to damage. Even just constant flash spammign will hold a group against a healer. The only reason tanks are loosing threat to healers is lazy/bad play.